The present invention relates to the field of photography and, more specifically, to photographic apparatus, such as a self-developing slide copier or printer configured to be supported on a table or desk, for effecting distribution of a fluid processing composition over an area of a self-developing film unit in response to manually withdrawing the film unit from the apparatus.
There are numerous self-developing photographic apparatus (cameras; slide copiers or printers; camera backs; etc.) configured for use with self-developing film units that are processed after exposure by manually advancing the film unit between a pair of pressure-applying rollers to rupture a pod at the leading end of the film unit holding a supply of fluid processing composition and effecting distribution of the fluid over the film unit image forming area between superposed negative and positive sheets. Following a suitable imbibition period, the sheets are manually separated to reveal a positive image print on the positive sheet. Examples of such film units include 665 and 668 Polaroid Land Film manufactured by Polaroid Corporation, Cambridge, Mass. The 665 film is a black and white film having an imbibition period of approximately 20 seconds; and the 668 film is a color film having an imbibition period of approximately 1 minute.
To optimize the uniformity of fluid distribution, it is highly desirable that the film unit be manually withdrawn along a preferred straight exit path that is symmetrically disposed with respect to the pair of juxtaposed pressure applying rollers. That is, the exit path should be substantially perpendicular to a plane that passes through the rollers and contains a film gap therebetween. While minor deviations from the preferred exit path are tolerable without seriously degrading the uniformity of the fluid distribution, substantial deviations from the preferred path, wherein the film unit is acutely inclined toward one of the pair of rollers, should be avoided because fluid distribution may become nonuniform to the point where some portions of the image area are treated with the processing fluid.
When an operator manually pulls the film unit from a self-developing photographic apparatus, he or she will most likely use a natural pulling motion without giving much thought to consciously withdrawing the film unit along the preferred exit path. Therefore, handheld self-developing cameras of this type have been provided with numerous devices, such as selectively pivoting handles, camera holding straps, and film motion guides, for automatically adjusting the orientation of the camera body to the operator's "natural pull path" or, in the case of the film guide, for altering this natural pull path so that the film is withdrawn along or in close proximity to the preferred film exit path. For examples of self-developing cameras having such film withdrawal aids, reference may be had to commonly assigned U.S. Pat. Nos. 3,522,766; 3,543,663; 3,625,126; 3,672,275; 3,678,832; and 4,044,365.
On the other hand, fixedly mounted self-developing photographic apparatus of this type that are configured to be supported on a table or desk when in operation generally do not include structure for aiding the user in withdrawing the film unit along the preferred exit path, which may be described in an accompanying instruction booklet as being parallel, or in some instances perpendicular to, the table top surface on which the apparatus is supported. In many instances, the operator will not remember to withdraw the film along this preferred exit path but rather will revert to the natural pulling motion so that the film is advanced along a natural pull path which deviates from the preferred exit path. Examples of such photographic apparatus in which the preferred film exit path is generally parallel to a table top support surface may be found in commonly-assigned U.S. Pat. Nos. 3,270,652 and 3,396,649. An example of an apparatus requiring that the film unit be withdrawn along a preferred path that is substantially perpendicular to the support surface may be found in commonly-assigned U.S. Pat. No. 3,796,485.
To aid the operator in timing the proper imbibition period, some self-developing cameras have been provided with a built-in timer system. For example, see commonly-assigned U.S. Pat. No. 3,608,454 which has an electronic timer that is actuated by a signal provided in response to withdrawing a film unit from the camera. The system may include a light which remains illuminated during the entire timed cycle and an electronic buzzer which provides an audible signal at the end of the timed cycle.
In many instances, it is desirable to process a plurality of film units in rapid sequence whereby their respective imbibition periods overlap. Because each film unit must be timed separately, and the camera only includes a single timer, the operator is forced to rely on auxiliary timing means such as his wristwatch or a wall clock to insure proper processing of the several film units. The use of multiple timing sources tends to be confusing and may lead to incorrectly timing the imbibition period of one or more of the sequentially processed film units.
Therefore, it is an object of the present invention to provide a self-developing photographic apparatus configured to be supported on a support surface and having its components arranged to take advantage of a natural pull path along which an operator most likely will pull the film unit to withdraw it from the apparatus so that fluid distribution is optimized.
It is another object of the invention to provide such an apparatus including structure for separately timing a predetermined imbibition period for each of a plurality of sequentially processed self-developing film units.
It is yet another object to provide such an apparatus that is simply constructed and easy to use.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.